The shooter, 53-year-old Cedric Anderson, walked into his wife’s North Park Elementary School classroom with a large rifle around 10:30 a.m. and opened fired with a .357-caliber revolver, the outlet reports.

Tragically, Anderson’s wife, Karen Elaine Smith, 53, was struck and killed, while two students were also shot. Anderson later turned the gun on himself, turning the incident into a murder-suicide.

Jonathan Martinez, an eight-year-old student in Smith’s class, later died from his injuries at Loma Linda University Medical Center. The other student, a nine-year-old boy, was reported to be in critical condition.

Investigators are searching for clues that point to a motive. Witnesses said Anderson walked into the school claiming that he had to drop something off for Smith, a special needs teacher.

According to San Bernardino Police Chief Jarrod Burguan, the couple was recently married.

“I’m told that their marriage was relatively short. They’ve only been married for a few months and they’ve been separated for about the last month, month-and-a-half, roughly, when this incident took place,” Burguan said. “But there’s nobody that in the investigation has come forward to say that they saw this coming.”

At the time of the shooting at least 15 students ranging from first to fourth grade were in the classroom, along with two aides.

The community banded together at a prayer vigil on Monday evening at Our Lady of the Assumption.

This is the second fatal incident within the last two years in San Bernardino. In December 2015, a couple opened fire at a holiday party held by the San Bernardino Health Department, killing 14 people.